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Bioactive peptides derived from food protein sources have been widely studied in the last years, and scientific researchers have been proving their role in human health, beyond their nutritional value. Several bioactivities have been attributed to these peptides, such as immunomodulatory, antimicrobial, antioxidant, antihypertensive, and opioid. Among them, metal-binding capacity has gained prominence. Mineral chelating peptides have shown potential to be applied in food products so as to decrease mineral deficiencies since peptide-metal complexes could enhance their bioavailability. Furthermore, many studies have been investigating their potential to decrease the Fe pro-oxidant effect by forming a stable structure with the metal and avoiding its interaction with other food constituents. These complexes can be formed during gastrointestinal digestion or can be synthesized prior to intake, with the aim to protect the mineral through the gastrointestinal tract. This review addresses: (i) the amino acid residues for metal-binding peptides and their main protein sources, (ii) peptide-metal complexation prior to or during gastrointestinal digestion, (iii) the function of metal (especially Fe, Ca, and Zn)-binding peptides on the metal bioavailability and (iv) their reactivity and possible pro-oxidant and side effects.

The CAP exerts potential prebiotic effects on different potentially probiotic Lactobacillus strains and should be an added-value ingredient for the food industry. © 2017 Society of Chemical Industry.

SummaryYeast biomass (Saccharomyces sp.) produced in local breweries as a by-product was utilized in this study. Percent proximate composition, amino acid composition, and protein nutritive value were determined for the yeast cell biomass (YC), a sodium perchlorate extracted and isoelectrically precipitated protein concentrate (P-PC), and a sodium trimetaphosphate treated extract followed by isoelectrical precipitation (TMP-PC). Protein concentrates averaged 75% protein as compared to 48.5% in the yeast biomass. Precipitation of the protein in the presence of either sodium perchlorate or sodium trimetaphosphate was reduced to 71% and 51% of the cell RNA content, respectively. Protein nutritive value was 70% of casein when measured by the protein efficiency ratio (PER), and over 90% of casein when net protein utilization (NPUa) was the criteria of evaluation.